Coolant Level and Light

[scotinoz]

So water pump and thermostat replaced along with timing belt. Though I had solved it as van ran fine for a few journeys, however when loaded up for camping and we hit some big hills I had the coolant bottle pressure issue again. Interestingly it seemed to take longer for it to happen. I though it could have been an air lock as the the hot air seems to come and go from the vent when up HI, but now having vented it off numerous times I am discounting that. Could it be the head gasket? Van is running fine apart from this issue with no smoking or hesitation. Coolant looks clean and pink. Any thoughts as to whether a heater matrix restriction could cause this over pressure?

[Silver Caravelle]

Assuming the new water pump and new thermostat are all good, that should rule out those as the culprits. And assuming the system has been fully bleed properly, there should not be any airlocks in the cooling system. Perhaps double check the coolant bottle cap is fully closed until it is clicked tight.

If it was a head gasket, typically there is going to be coolant loss and potentially dirty coolant. Can only hope it is not this!

Recheck all coolant hoses and clamps to ensure no pin hole air leaks, and/ or coolant leaks.

The only other suggestions I have is the aircon and main radiators and whether there is a blockage ( probably unlikely) or too much crap or insects on the outside of them reduciing airflow and therefore cooling efficiency.

Maybe re bleed the cooling system (with heater turned on to allow full circulation of coolant ) and also run to operating temperature ( stationary) with the coolant bottle cap off and then observe coolant starting to rise to vent any air bubbles and then put cap on and fully close it. Hopefully there should not be any air locks.

Are both radiator fans kicking it when they are supposed to?

Scott.

[Silver Caravelle]

Gday,

I noticed your other posts today regarding installing an oil cooler. Did you rule out the above suggestions and your concern regarding the head gasket? Any coolant loss?

There must be an underlying cause of the cooling system over pressurising without having to resort to an oil cooler. Maybe add a new coolant expansion bottle cap to rule out unnecessary coolant release from the bottle. Apart from that, I am all out of suggestions!

Cheers,

Scott

[scotinoz]

I have ordered a gas tester kit for CO2 in the coolant but still not got to the bottom of the problem. Agree I should not have to install the oil cooler although I would like to lower the oil temps anyway so its a no regret upgrade. I will probably fit a new cap as well as its too cheap an option to discount. I don't appear to be losing any coolant although to be honest I am leaning toward a head gasket issue, albeit a minor one it would appear as the van runs fine and is ok for hours of driving when not working hard.

[scotinoz]

Does anyone know if the coolant bottle cap just has a pressure release valve for over pressure? Is there a secondary valve or function for any purpose?